2001-2007 LB7 / LLY / LBZ Duramax OEM Placement Coolant Tank Kit

Jason Wehrli:

Today, we are going to show you our Duramax fabricated aluminum coolant tank kits.


All right, the fabricated aluminum coolant tank for the Duramax platform. The Duramax has been a long-running platform from 2001 to the current model year 2024, and there have been many different RPO codes over those years and many improvements to keep up with the horsepower ratings on these engines. So we offer a coolant tank for every model year RPO code, starting with the '01 to '07, your classic body style trucks, a little bit larger tank on the passenger side, right behind that air box. Then, the LMM is not pictured here on the table. It is very similar looking to the LML tank, which is this candy blue one in front of us, 11 to 16 again sitting right behind that passenger air intake box. And then from there, we move into our first-gen L5P, which is your 17 to 19 L5P platform, and they move the coolant tank back to the firewall on the passenger side this model year.


Then, in the 2020 model year, with the body change, GM moved the coolant tank from the passenger side to the driver's side on the firewall. It's a much larger style tank over there. But all of these tanks, again, as I mentioned, are meant as an OEM drop-in replacement. So these tanks we designed in CAD on the computer, we're able to design them with a very precise fit using OEM style mounting locations, connecting to OEM style hoses, and fitting right in that factory location just as the OEM tank did for the least amount, and in most cases, no modifications of anything in the surrounding area. Our tanks are manufactured here in-house, starting as a flat aluminum sheet on our laser. We laser cut the flat sheets, and then they move to our CNC press break, where they get bent. From there, they move into the fabrication shop where they get TIG welded together, adding all of the necessary bungs and fittings, welding up all of the seams, and adding that WCFab logo on the top.


Another standard component on all of our OEM placement coolant tanks is our high-quality billet aluminum sight glass. We pre-install these sight glasses after powder coat before they get wrapped up to ship out. It's a very fine thread, very, very easy to cross-thread. So we apply the proper lubrication and torque that sight glass to the proper torque so that you don't have to worry about messing with that when you receive your cooling tank. The sight glass offers a quick and easy view of your coolant level when you pop the hood on top of all the coolant tanks. The filler neck CNC machined here in-house accepts our high-quality billet aluminum black anodized coolant tank cap; all tanks come standard with the black anodized cap. We do offer available as a separate purchase, a clear anodized version if you would rather have that clear look.


Then, for our coolant overflow port, we have our little hose barb for that, as well as our preformed rubber hose. Finishing off that installation for a nice OEM-style look. One other item here is our coolant level sensor. In all of the OEM tanks on the Duramax trucks, the factory coolant level sensor is incorporated and molded into the tank and is a non-serviceable item. The 2017 to current L5P are notorious for coolant level sensor issues requiring complete replacement of that OEM tank when those factory sensors become faulty. So we supply a thread-in style, serviceable, low-cooling sensor. The last item we'll touch on here is the tank in the center, which has our optional powder coat WCfab tag. All tanks come standard with a raw style tag. If you use a two-coat color, that tag will have a clear coat. With a single-coat standard color like this flat black one, there will be a raw aluminum brushed finish tank in front of us in the center through the candy red, much smaller in size; that is our twin turbo style tank for 2001 to 2019 models.


And these are not drop-in-style replacement tanks. The twin-turbo-style tank is manufactured for DIY builders looking to build a custom turbo setup, compound turbo applications, or racing applications. These style tanks are much smaller and more compact in size and sit closer to the passenger side fender, allowing more room for larger and additional turbochargers. In most cases, they require relocation or removal of your passenger-side battery and rerouting of other OEM-style components. So, if you want to replace your OEM tank in the OEM location, ensure you're getting the OEM-style tank and not the twin-turbo-style tank.

So why would you be upgrading the coolant tank on your Duramax? Many of these models of Duramax have some notorious coolant level sensor issues that require the replacement of the OEM tank. So if you've got to replace that OEM tank, you might as well spice up the underhood a little bit, give yourself a nicer-looking, more reliable aluminum-fabricated tank, and serviceable sensor, and add a little color underneath the hood.


That's the second reason you might upgrade. If you've got all of our other upgraded underhood components, the Intercooler Plumbing, upgraded powder-coated turbocharger intake systems, and all those good-looking parts, those OEM coolant tanks are a pretty unsightly look right behind a nice fabricated aluminum airbox, especially on the older model of year trucks. The tanks become yellow over time, and if you've had a truck that's had head gasket issues, they'll even become very black and dirty inside, and there's no good way to clean them out. So upgrading that cooling tank is a nice final touch to your engine bay as another fabricated custom powder-coated component.